1. Field of the Invention
The present invention relates to a technique of processing an electronic document, and more particularly, to a document processing apparatus capable of outputting video data related to electronic document data.
2. Description of the Related Art
WWW (World Wide Web) is widely used to supply hypertext information via the Internet.
The WWW is a system that allows electronic document to be treated in a new manner, that is, generated, processed, disclosed, and used in common. However, from the point of view of practically using documents, the WWW has a limitation in the capability of processing documents. Thus, there is a need for a higher-level document processing technique such as categorization or summarization of documents. In order to realize such high-level document processing, it is necessary to automatically process the contents of documents.
However, such automatic processing of the contents of documents has difficulties as described below.
Firstly, the HTML (Electronic Markup Language) prescribes the manner of representing documents, but does not prescribe the contents of the documents. Secondly, it is not necessarily easy for users to understand the contents of documents that are linked to one another via a hypertext network. Thirdly, authors usually write documents without bearing in mind the convenience of readers, and no adjustment is made as to the difference in convenience between authors and readers.
Although the WWW is a new electronic documentation system having various advantages, the WWW is not capable of performing high-level document processing which needs additional automatic processing. In other words, in order to realize the high-level document processing, it is required to automatically process documents.
To the above end, systems for assisting in automatically processing a document has been developed on the basis of natural language processing technology. One such method is to automatically process a document according to tags which have been attached, by the author of the document or other person, to the document so as to represent attribute information about the internal structure of the document.
In recent years, computers have become increasingly popular, and many computers are connected to one another via a network. As a result, there occurs a need for a higher-level document processing technique to perform generation of a text document, labeling, and a modification of a text document, in accordance with an index depending upon the content of a document. More specifically, there is a need for a technique to summarize or categorize a document in response to a request issued by a user.
There is also a need for a document viewer capable of displaying a document and a summary thereof in a desirable manner depending upon the type of a display device. Furthermore, there is a need for a technique of reading aloud text data when the text data is displayed. It is more desirable to read aloud text data in synchronization with the operation of displaying the text data or an image.
If video data such as a motion image or a still image related to document data is output, a user can easily obtain various kinds of high-level information. Thus, it is desirable to provide a technique for outputting video data in synchronization with various operations performed upon document data.